Creating an accumulating count by date in a line chart?

[#1]

I have data from Salesforce, and want to show the growing monthly total for our contacts, i.e. count(name) for the x-axis value Date(MonthStart(CreatedDate)) plus all dates before it. I could only find answers pertaining to sums, but I'm not counting a numerical value. How can I do this?

Ex.

ID	Name	CreatedDate
209570270	Name1	1/5/15
235920952	Name2	2/5/15
252000980	Name3	2/5/15
345989453	Name4	3/5/15
340958092	Name5	5/5/15
235092435	Name6	6/5/15

Desired Line Chart

[Gysbert_Wassenaar · Accepted solution]

Try rangesum(above(count(name),0, rowno()). You'll want to add a dummy record for the missing date too. See attached example.

[#3]

Perfect, thanks!